[二氧化矽粒子分散液之製造方法] 本發明之二氧化矽粒子分散液之製造方法包含：準備實質上包含有機溶劑之液體I之步驟；及於該液體I中同時添加含有矽烷烷氧化物之液體A、及含有鹼性觸媒及水之液體B，而使矽烷烷氧化物水解及縮聚，製造包含2個以上之一次粒子連結而成之異形二氧化矽粒子之分散液的步驟。此時，將自添加開始(反應開始)直至達到添加結束時(反應結束時)之反應系(分散液)中之二氧化矽濃度之70%之濃度之時間設為總添加時間(總反應時間)之20%以下。 藉此，於反應初期，快速提高系統中之活性二氧化矽粒子(一次粒子)之濃度，促進一次粒子之積極合著，因此可有效率地製造一次粒子合著而得之異形二氧化矽粒子。 自添加開始(反應開始)直至達到添加結束時(反應結束時)之系統中二氧化矽濃度之70%之濃度之時間較佳為總添加時間(總反應時間)之15%以下。 此處，所謂2個以上之一次粒子連結而成之異形二氧化矽粒子，係指作為球狀或真球狀之1個粒子所掌握之粒子(一次粒子)為2個以上，較佳為2～10個連結而成之鏈狀粒子(參照圖1)。 又，系統中二氧化矽濃度之測定係每10分鐘採取樣品，使樣品5 g於1000℃下乾燥1小時，根據乾燥前後之質量求出(下述式)。 系統中二氧化矽濃度(質量%)＝(乾燥後之質量/乾燥前之質量)×100 作為將自添加開始(反應開始)直至達到添加結束時(反應結束時)之系統中二氧化矽濃度之70%之濃度之時間設為總添加時間(總反應時間)之20%以下之方法，可列舉減少液體I之量，或提高反應初期之矽烷烷氧化物之添加濃度、添加速度之方法。 ＜液體I(預先準備於容器之液體)＞ 液體I實質上包含有機溶劑。作為有機溶劑，可列舉醇、酮、醚、二醇、酯等。其中，就可容易地使矽烷烷氧化物擴散並均勻且迅速地推進水解之方面而言，較佳為醇。更具體而言，可列舉：甲醇、乙醇、丙醇、丁醇等醇；甲基乙基酮、甲基異丁基酮等酮；甲基溶纖劑、乙基溶纖劑、丙二醇單丙醚等二醇醚；乙二醇、丙二醇、己二醇等二醇；乙酸甲酯、乙酸乙酯、乳酸甲酯、乳酸乙酯等酯。該等之中，更佳為甲醇或乙醇，尤佳為甲醇。該等有機溶劑可單獨使用1種，亦可將2種以上混合使用。 此處，所謂「實質上包含有機溶劑」，係意指可包含自有機溶劑之製造過程不可避免地包含之雜質等，但不含其以外者。例如，有機溶劑為99質量%以上，較佳為99.5質量%以上。 作為液體I之量，相對於液體A及液體B之總添加量，較佳為30質量%以下，更佳為15質量%以下，進而較佳為0.1～10質量%。藉由如此將液體I之量設為少量，於反應初期，可快速提高系統中之活性二氧化矽粒子(一次粒子)之濃度，促進一次粒子之合著。 再者，於先前之反應系中，由於預先於液體I中放入鹼性觸媒或水，故而自添加開始時(反應開始時)，系統內之組成逐次產生變化，因此矽烷烷氧化物之水解條件並非固定，容易產生未反應物。又，添加開始時(反應開始時)之pH值較高，但其後有pH值降低之傾向，於追加之鹼性觸媒不足之情形時，添加結束時(反應結束時)之pH值低於11之情況較多，因此容易產生未反應物。 相對於此，於本發明中，由於使用實質上包含有機溶劑之液體I，故而於自添加開始(反應開始)直至結束之反應期間中，可將鹼性觸媒及水相對於矽烷烷氧化物之量設為固定。藉此，逐次添加之矽烷烷氧化物始終於相同之條件下水解，因此未生長至製造目標二氧化矽粒子之低聚物等未反應物之生成受到抑制。又，可製造一次粒徑一致之粒子。 ＜液體A＞ 液體A係含有矽烷烷氧化物者，較佳為進而含有有機溶劑。通常為實質上包含矽烷烷氧化物，或實質上包含矽烷烷氧化物及有機溶劑之兩種成分。再者，所謂「實質上包含矽烷烷氧化物」、「實質上包含兩種成分」，與上述相同，係意指可包含自矽烷烷氧化物或有機溶劑之製造過程不可避免包含之雜質等，但不含其以外者，例如為99質量%以上，較佳為99.5質量%以上。 作為矽烷烷氧化物，可列舉下述式[1]所表示者。 Xn
Si(OR)4-n
・・・[1] 式中，X表示氫原子、氟原子、碳數1～8之烷基、芳基或乙烯基，R表示氫原子、碳數1～8之烷基、芳基或乙烯基，n表示0～3之整數。 作為上述式[1]所表示之矽烷烷氧化物，除四甲氧基矽烷、四乙氧基矽烷以外，可列舉：四異丙氧基矽烷、四丁氧基矽烷、四辛氧基矽烷、甲基三甲氧基矽烷、甲基三乙氧基矽烷、甲基三異丙氧基矽烷、乙基三甲氧基矽烷、乙基三乙氧基矽烷、乙基三異丙氧基矽烷、辛基三甲氧基矽烷、辛基三乙氧基矽烷、乙烯基三甲氧基矽烷、乙烯基三乙氧基矽烷、苯基三甲氧基矽烷、苯基三乙氧基矽烷、三甲氧基矽烷、三乙氧基矽烷、三異丙氧基矽烷、氟三甲氧基矽烷、氟三乙氧基矽烷、二甲基二甲氧基矽烷、二甲基二乙氧基矽烷、二乙基二甲氧基矽烷、二乙基二乙氧基矽烷、二甲氧基矽烷、二乙氧基矽烷、二氟二甲氧基矽烷、二氟二乙氧基矽烷、三甲基甲氧基矽烷、三甲基乙氧基矽烷、三甲基異丙氧基矽烷、三甲基丁氧基矽烷、三氟甲基三甲氧基矽烷、三氟甲基三乙氧基矽烷等。 該等矽烷烷氧化物中，尤其較佳為使用四甲氧基矽烷(TMOS)或四乙氧基矽烷(TEOS)等上述式[1]之n為0、且R之烷基鏈較短者。於使用該等之情形時，水解速度變快，可迅速提高二氧化矽粒子之初始濃度，又，有不易殘留未反應物之傾向。其中較佳為烷基鏈較短之四甲氧基矽烷(TMOS)。 作為液體A之有機溶劑，可使用上述液體I所例示者，較佳為使用與液體I相同組成之有機溶劑。即，於在液體I中使用甲醇之情形時，較佳為於液體A中亦使用甲醇。 此處，於液體A包含有機溶劑之情形時，作為矽烷烷氧化物相對於有機溶劑之濃度，例如為1.5～6.4 mol/L，較佳為2.0～6.0 mol/L。 ＜液體B＞ 液體B係含有鹼性觸媒及水者，通常實質上包含兩種成分。再者，所謂「實質上包含兩種成分」，係與上述液體A中說明者相同之意義。 作為鹼性觸媒，可使用氨、胺、鹼金屬氫化物、鹼土金屬氫化物、鹼金屬氫氧化物、鹼土金屬氫氧化物、四級銨化合物、胺系偶合劑等顯示鹼性之化合物，較佳為使用氨。 此處，作為鹼性觸媒相對於水之濃度，例如為1～24 mol/L，較佳為3～15 mol/L。 ＜反應條件等＞ 二氧化矽粒子分散液之製造方法較佳為滿足以下兩個條件。 (1)開始液體A及液體B之添加後直至結束之期間(自添加開始(反應開始)直至結束之期間)之反應系中之鹼性觸媒相對於矽烷烷氧化物之莫耳比相對於初期值之變化率(觸媒比率變化率)為0.90～1.10， (2)開始液體A及液體B之添加後直至結束之期間(自添加開始(反應開始)直至結束之期間)之反應系中之水相對於矽烷烷氧化物之莫耳比相對於初期值之變化率(水比率變化率)為0.90～1.10。 即，於自添加開始(反應開始)直至結束之期間，儘量減少觸媒比率變化率及水比率變化率，而欲設為固定。作為其具體之態樣，如上所述，可列舉預先儘量減少液體I中所含之鹼性觸媒及水之量，藉此抑制觸媒比率變化率及水比率變化率之方法。又，可列舉於自添加開始(反應開始)直至結束之期間，儘可能將液體A及液體B之添加速度等添加條件設為固定，而抑制觸媒比率變化率及水比率變化率之方法。例如，藉由使用高精度之泵，可抑制液體A及液體B之添加速度之變化。 藉此，逐次添加之矽烷烷氧化物始終於相同之條件下水解，未生長至製造目標之二氧化矽粒子之低聚物等未反應物之生成受到抑制。因此，可省略去除未反應物之步驟，可有效率地製造二氧化矽粒子分散液。又，該製造之二氧化矽粒子分散液幾乎不含低聚物等未反應物。因此，可獲得二氧化矽粒子分散液及作為研磨材之穩定性優異、具有良好之研磨特性之研磨材。進而，可製造一次粒徑一致之粒子。 此處，鹼性觸媒相對於矽烷烷氧化物之莫耳比(鹼性觸媒/矽烷烷氧化物)、及水相對於矽烷烷氧化物之莫耳比(水/矽烷烷氧化物)分別根據添加重量實測值算出。此時，假定矽烷烷氧化物之水解及縮聚之反應為瞬時發生，而鹼性觸媒未向系統外釋出。觸媒比率變化率及水比率變化率係根據每特定時間(例如每10分鐘)，根據添加重量實測值算出反應系內之莫耳比，除以初期之莫耳比之數值而算出。再者，所謂初期值，係指剛添加液體A及液體B後之莫耳比(理論值)。 該觸媒比率變化率如上所述，較佳為0.90～1.10，更佳為0.95～1.05，進而較佳為0.98～1.02。 該水比率變化率如上所述，較佳為0.90～1.10，更佳為0.95～1.05，進而較佳為0.98～1.02。 又，矽烷烷氧化物之添加速度於自添加開始(反應開始)直至結束之期間，較佳為0.005 mol/分鐘以上，更佳為0.01 mol/分鐘以上，進而較佳為0.02 mol/分鐘以上。藉由以此種速度添加矽烷烷氧化物，可抑制未生長至目標二氧化矽粒子之矽烷烷氧化物之低聚物等未反應物之生成。又，於反應之初期階段，可形成大量表面為活性之一次粒子，使該一次粒子彼此接觸併合著，並且可進而使該合著粒子作為種子粒子生長。 進而，於自添加開始(反應開始)直至結束之期間之反應系中，鹼性觸媒相對於矽烷烷氧化物之莫耳比始終為0.20以上，且水相對於矽烷烷氧化物之莫耳比始終為2.0以上。即，較佳為添加之間(反應中)，相對於矽烷烷氧化物，將鹼性觸媒及水保持為特定量以上。藉由如此將鹼性觸媒及水保持為特定量以上而使之反應，可充分地推進水解，並可抑制未反應之矽烷烷氧化物之殘留、或未反應物之產生。 再者，鹼性觸媒相對於矽烷烷氧化物之莫耳比、及水相對於矽烷烷氧化物之莫耳比與上述相同，係指分別基於添加重量實測值算出者。 此處，於自添加開始(反應開始)直至結束之期間之反應系中，鹼性觸媒相對於矽烷烷氧化物之莫耳比如上所述，較佳為0.20以上，更佳為0.30以上，進而較佳為0.50～1.00。 又，於自添加開始(反應開始)直至結束之期間之反應系中，水相對於矽烷烷氧化物之莫耳比如上所述，較佳為2.0以上，更佳為3.0以上，進而較佳為3.5～15.0。 又，於添加結束時(反應結束時)之反應系中，pH值較佳為11以上，更佳為11.2以上。於預先於液體I中放入鹼性觸媒之先前之反應系中，多數情況為於反應結束時pH值低於11，成為產生未反應物之主要原因。於本發明中，如上所述，藉由將鹼性觸媒量或水量相對於矽烷烷氧化物設為固定而進行添加，可使反應結束時之pH值成為11以上。 該反應通常於常壓下進行。作為反應溫度，只要為所使用之溶劑之沸點以下之溫度即可，但為加快粒子之析出，較佳為0～65℃，更佳為10～50℃。 藉由本發明之製造方法製造之二氧化矽粒子分散液係矽烷烷氧化物之低聚物等未反應物之生成較少。因此，未必必須進行先前進行之加熱熟成處理、加熱去除處理、超濾等精製處理。 又，添加結束時(反應結束時)之二氧化矽粒子分散液(反應系)中之二氧化矽濃度高於利用先前之方法製造者，例如為5質量%以上，較佳為10質量%以上，更佳為10～25質量%。 [二氧化矽粒子分散液] 本發明之二氧化矽粒子分散液包含2個以上之平均粒徑(d)為5～300 nm之一次粒子連結而成之異形二氧化矽粒子10%以上，未反應物之含量為200 ppm以下。二氧化矽粒子分散液可藉由上述製造方法製造。二氧化矽粒子分散液對研磨材有用，可直接於分散體之狀態下使用，亦可乾燥而使用。 ＜未反應物＞ 所謂未反應物，係意指反應未進行至目標二氧化矽粒子之含矽化合物。例如未反應之原料矽烷烷氧化物或其低分子水解物(低聚物)、遠小於目標粒子之粒子等。具體而言，係意指使用日立工機股份有限公司製造之小型超離心機CS150GXL，對二氧化矽粒子水分散液於設定溫度10℃、1,370,000 rpm(1,000,000 G)下進行30分鐘離心處理時之上澄液中存在之含矽化合物。 《未反應物之含量之測定方法》 根據對存在於上述上澄液中之含矽化合物(未反應物)，利用島津製作所股份有限公司製造之ICP(Inductively Coupled Plasma，感應耦合電漿)發光分析裝置ICPS-8100測得之Si求出SiO2
濃度。 由於二氧化矽粒子分散液幾乎不含低聚物等未反應物，故而於用於研磨材之情形時，研磨材中之粒子穩定性優異，並且向基板之附著物減少。又，可抑制添加至研磨材之各種藥品之吸附或與各種藥品之反應，而有效地發揮各種藥品之效果。 二氧化矽粒子分散液中所含之二氧化矽粒子採用三維縮聚結構。其原因在於，矽烷烷氧化物之水解及縮聚於鹼性側進行，藉此並非僅平面狀(二維)地進行，而是立體(三維)地進行。使用具有此種結構之粒子之研磨材係粒子之分散性較高，可獲得充分之研磨速度，因此較佳。另一方面，若於酸性側進行水解及縮聚，則二維地進行，無法獲得球狀粒子。 該結構可利用穿透式電子顯微鏡或掃描式電子顯微鏡確認，根據以粒子之形式存在而進行判斷。 二氧化矽粒子分散液中所含之一次粒子之平均粒徑(d)為5～300 nm，可根據所要求之研磨速度或研磨精度等適當設定。關於平均粒徑(d)之算出方法，使用圖1進行說明。圖1例示有一次粒子單個存在之粒子或複數個一次粒子連結而得之粒子。塗黑部分係粒子間之接合部之圖像，接合部亦可包含空間。粒徑d係測定各粒子之一次粒子之最長徑而得者。平均粒徑(d)係拍攝電子顯微鏡照片，對任意之100個粒子測定各粒子之一次粒子之最長徑d，以其平均值之形式而獲得。 此處，於平均粒徑未達5 nm之情形時，有二氧化矽粒子分散液之穩定性變得不充分之傾向，又，粒徑過小而無法獲得充分之研磨速度。於平均粒徑超過300 nm之情形時，於用作研磨材之情形時，亦基於基板或絕緣膜之種類而異，但有容易產生刮痕，無法獲得充分之平滑性之情況。平均粒徑較佳為10～200 nm，更佳為15～100 nm。 二氧化矽粒子分散液係包含2個以上之上述平均粒徑(d)為5～300 nm之一次粒子連結而成之異形二氧化矽粒子10%以上者，較佳為包含30%以上，更佳為包含50%以上。異形二氧化矽粒子只要為2個以上之一次粒子連結而得者則並無特別限制，較佳為2～10個左右連結而得者。 此處，異形二氧化矽粒子之一次粒子之連結個數、或系統中之異形二氧化矽粒子之比率(異形粒子率)係拍攝電子顯微鏡照片，對任意之100個粒子進行觀察而求出。 二氧化矽粒子分散液中所含之二氧化矽粒子較佳為U、Th各自之含量未達0.3 ppb，鹼金屬、鹼土金屬、Fe、Ti、Zn、Pd、Ag、Mn、Co、Mo、Sn、Al、Zr各自之含量未達0.1 ppm，Cu、Ni、Cr各自之含量未達1 ppb。若為該範圍，則可用作配線節點為40 nm以下之高積體之邏輯電路或記憶體及三維安裝用調製用之研磨粒。 若該等雜質之金屬元素之含量超過上述範圍而大量存在，則有於使用二氧化矽粒子進行過研磨之基板殘留金屬元素之虞。該金屬元素引起形成於半導體基板之電路之絕緣不良，使電路短路。藉此，有設置於絕緣用之膜(絕緣膜)之介電常數降低，金屬配線中阻抗增大，產生應答速度慢、消耗電力增大等之情況。又，於金屬元素離子移動(擴散)，使用條件或使用持續長期之情形時亦有產生此種故障之情況。尤其是於U、Th之情形時，由於產生輻射，故而於在即使微量殘留之情形時亦引起因輻射導致之半導體之誤動作方面而言，欠佳。 此處，所謂鹼金屬，係表示Li、Na、K、Rb、Cs、Fr，所謂鹼土金屬，係表示Be、Mg、Ca、Sr、Ba、Ra。 為獲得此種雜質之含量較少之高純度二氧化矽粒子，較佳為將製備粒子時之裝置之材質設為不含該等元素、且耐化學品性較高者，具體而言，較佳為Teflon(註冊商標)、FRP(Fiber Reinforced Plastics，纖維強化塑膠)、碳纖維等塑膠、無鹼玻璃等。 又，關於所使用之原料，較佳為利用蒸餾、離子交換、過濾器去除而進行精製。尤其是用於烷氧化物之水解時之乙醇有來自槽等之金屬雜質或合成時之觸媒殘留之虞，有必需精度特別高之精製之情況。 作為獲得高純度二氧化矽粒子之方法，如上所述，有預先準備雜質較少之原料，抑制自粒子製備用裝置混入之方法。除此以外，亦可自未充分採取此種對策而製備之粒子減少雜質。然而，於雜質引入至二氧化矽粒子內之情形時，有利用離子交換或過濾器去除進行精製時效率較低、成本變高之虞。因此，利用此種方法，獲得雜質之含量較少之二氧化矽粒子不實際。 《金屬元素含量之測定》 關於二氧化矽粒子中之U、Th之含量，鹼金屬、鹼土金屬、Fe、Ti、Zn、Pd、Ag、Mn、Co、Mo、Sn、Al、Zr之含量，及Cu、Ni、Cr之含量，係利用氫氟酸使二氧化矽粒子溶解，進行加熱而去除氫氟酸後，視需要添加純水，對所獲得之溶液使用ICP感應耦合電漿發射光譜質量分析裝置(例如島津製作所股份有限公司製造之ICPM-8500)進行測定。 [實施例] 以下，藉由實施例說明本發明，但本發明並不限定於該等實施例。 [實施例1] ＜二氧化矽粒子分散液(SA)之製造＞ 將甲醇(液體I)300.0 g保持為50℃，對該液體I，花費5小時同時添加四甲氧基矽烷(多摩化學工業股份有限公司製造，以下相同)之甲醇溶液(液體A)2994.4 g、及氨水(液體B)800.0 g。反應結束時之二氧化矽粒子分散液之二氧化矽濃度為14.2質量%。添加結束後，進而於該溫度下熟成1小時。將溶劑置換為純水，獲得二氧化矽濃度20質量%之二氧化矽粒子分散液(SA)。將詳細之處理條件、及各種測定結果示於表1。又，將觸媒比率變化率及水比率變化率之經時變化示於圖2。進而，將系統內二氧化矽濃度之變化示於圖3。 《鹼性觸媒及水之相對於矽烷烷氧化物之莫耳比、及其變化率》 鹼性觸媒/矽烷烷氧化物、水/矽烷烷氧化物之各莫耳比係根據添加重量實測值，假定矽烷烷氧化物之水解及縮聚之反應為瞬時產生，鹼性觸媒未向系統外釋出而算出。自液體A及液體B之添加開始10分鐘後，算出每10分鐘之反應系內之莫耳比。將剛添加液體A及液體B後之莫耳比(理論值)設為初期值，利用除以該初期值而得之數值，對系統內之各物質莫耳比之變化進行比較。 Si(OR)4
＋4H2
O→Si(OH)4
＋4ROH (於水解時消耗4莫耳) Si(OH)4
→SiO2
＋2H2
O (於縮聚時釋出2莫耳) 《系統中二氧化矽濃度》 每10分鐘採取樣品，使樣品5 g於1000℃下乾燥1小時，根據乾燥前後之質量，算出系統中二氧化矽濃度(下述式)。 系統中二氧化矽濃度(質量%)＝(乾燥後之質量/乾燥前之質量)×100 《未反應物量》 未反應物量係利用根據對使用日立工機股份有限公司製造之小型超離心機CS150GXL，對所獲得之二氧化矽濃度20質量%之二氧化矽粒子分散液，於設定溫度10℃、1,370,000 rpm(1,000,000 G)下進行30分鐘離心處理時之上澄液中存在之含矽化合物(未反應物)，利用島津製作所股份有限公司製造之ICP發光分析裝置ICPS-8100測得之Si求出之SiO2
濃度進行比較。 《一次粒子之平均粒徑》 一次粒子之平均粒徑係拍攝二氧化矽粒子之電子顯微鏡照片，對任意之100個粒子，如圖1所例示，測定一次粒子之直徑最長之部分(亦有鏈狀粒子之短徑方向之情況)，以其平均值之形式而獲得。 《一次粒徑之CV值》 一次粒徑之CV值係使用上述各個結果，藉由計算求出。 《系統中之異形二氧化矽粒子之比率(異形粒子率)》 拍攝電子顯微鏡照片，對任意之100個粒子進行觀察，求出2個以上之一次粒子連結而成之異形二氧化矽粒子之比率。 《異形二氧化矽粒子之一次粒子之連結個數》 拍攝電子顯微鏡照片，對任意之100個粒子進行觀察，求出各粒子之連結個數之平均值。 ＜研磨材(SA)之製造＞ 製備含有實施例1中製造之二氧化矽粒子3.0質量%、羥乙基纖維素(HEC)175 ppm、氨225 ppm之研磨材(SA)。 《研磨材(漿料)之穩定性試驗》 研磨材(漿料)之穩定性係根據＜研磨材(SA)之製造＞中製備之研磨材(SA)有無白濁進行評價。將結果示於表1。 無白濁：○ 有白濁：× 《研磨試驗》 使用研磨用基板(結晶結構為1.0.0之單晶矽晶圓)，安裝於研磨裝置(Nano Factor股份有限公司製造之NF300)，以研磨墊SUBA600、基板負荷15 kPa、工作台旋轉速度50 rpm、主軸速度60 rpm，對上述研磨材(SA)，以250 ml/分鐘之速度進行研磨用基板之研磨10分鐘。其後，利用純水清洗並風乾。 其後，觀察所獲得之研磨基板之研磨表面，利用以下基準(刮痕之程度)對表面之平滑性進行評價。將結果示於表1。 幾乎見不到刮痕。：○ 見到一點點刮痕。：△ 見到大範圍刮痕。：× 關於研磨基板上之二氧化矽成分之殘留，使用雷射顯微鏡(KEYENCE股份有限公司製造之VK-X250)確認殘留之程度，利用下述評價基準進行評價。將結果示於表1。 幾乎見不到殘留。：○ 見到一點點殘留。：△ 見到大範圍殘留。：× [實施例2] ＜二氧化矽粒子分散液(SB)之製造＞ 將甲醇(液體I)206.0 g保持為25℃，對該液體I，花費10小時同時添加四甲氧基矽烷之甲醇溶液(液體A)2003.3 g、及氨水(液體B)784.0 g。反應結束時之二氧化矽粒子分散液之二氧化矽濃度為12.9質量%。添加結束後，進而於該溫度下熟成1小時。將溶劑置換為純水，獲得二氧化矽濃度20質量%之二氧化矽粒子分散液(SB)。將詳細之處理條件、及各種測定結果示於表1。又，將觸媒比率變化率及水比率變化率之經時變化示於圖4。進而，將系統內二氧化矽濃度之變化示於圖5。 使用二氧化矽粒子分散液(SB)，除此以外，以與實施例1相同之方式製造研磨材(SB)，並以與實施例1相同之方式進行穩定性試驗及研磨試驗。將結果示於表1。 [實施例3] ＜二氧化矽粒子分散液(SC)之製造＞ 將甲醇(液體I)150.0 g保持為60℃，對該液體I，花費5小時同時添加四甲氧基矽烷之甲醇溶液(液體A)2994.4 g、及氨水(液體B)800.0 g。反應結束時之二氧化矽粒子分散液之二氧化矽濃度為14.7質量%。添加結束後，進而於該溫度下熟成1小時。將溶劑置換為純水，獲得二氧化矽濃度20質量%之二氧化矽粒子分散液(SC)。將詳細之處理條件、及各種測定結果示於表1。又，將觸媒比率變化率及水比率變化率之經時變化示於圖6。進而，將系統內二氧化矽濃度之變化示於圖7。 使用二氧化矽粒子分散液(SC)，除此以外，以與實施例1相同之方式製造研磨材(SC)，並以與實施例1相同之方式進行穩定性試驗及研磨試驗。將結果示於表1。 [實施例4] ＜二氧化矽粒子分散液(SD)之製造＞ 將甲醇(液體I)500.0 g保持為40℃，對該液體I，花費8小時20分鐘(500分鐘)同時添加四甲氧基矽烷之甲醇溶液(液體A)2794.4 g、及氨水(液體B)800.0 g。反應結束時之二氧化矽粒子分散液之二氧化矽濃度為14.2質量%。添加結束後，進而於該溫度下熟成1小時。將溶劑置換為純水，獲得二氧化矽濃度20質量%之二氧化矽粒子分散液(SD)。將詳細之處理條件、及各種測定結果示於表1。又，將觸媒比率變化率及水比率變化率之經時變化示於圖8。進而，將系統內二氧化矽濃度之變化示於圖9。 使用二氧化矽粒子分散液(SD)，除此以外，以與實施例1相同之方式製造研磨材(SD)，並以與實施例1相同之方式進行穩定性試驗及研磨試驗。將結果示於表1。 [比較例1] ＜二氧化矽粒子分散液(RA)之製造＞ 將包含甲醇2268.0 g、純水337.5 g、29%氨水94.5 g之液體I保持為40℃，對該液體I，花費160分鐘添加四甲氧基矽烷之甲醇溶液(液體A)2170.0 g。反應結束時之二氧化矽粒子分散液之二氧化矽濃度為14.0質量%。添加結束後，進而於該溫度下熟成1小時。將溶劑置換為純水，獲得二氧化矽濃度20質量%之二氧化矽粒子分散液(RA)。將詳細之處理條件、及各種測定結果示於表1。又，將觸媒比率變化率及水比率變化率之經時變化示於圖10。進而，將系統內二氧化矽濃度之變化示於圖11。 使用二氧化矽粒子分散液(RA)，除此以外，以與實施例1相同之方式製造研磨材(RA)，並以與實施例1相同之方式進行穩定性試驗及研磨試驗。將結果示於表1。 再者，於任一實施例及比較例中，二氧化矽粒子中之U、Th各自之含量均未達0.3 ppb，鹼金屬、鹼土金屬、Fe、Ti、Zn、Pd、Ag、Mn、Co、Mo、Sn、Al、Zr各自之含量均未達0.1 ppm，Cu、Ni、Cr各自之含量均未達1 ppb。 《金屬元素含量》 關於二氧化矽粒子中之各金屬元素量之含量，係利用氫氟酸使二氧化矽粒子溶解，進行加熱而去除氫氟酸後，視需要添加純水，對所獲得之溶液使用ICP感應耦合電漿發射光譜質量分析裝置(例如島津製作所股份有限公司製造之ICPM-8500)進行測定。 [表1]
如表1所示，可知，實施例1～4中製造之二氧化矽粒子分散液有效率地生成異形二氧化矽粒子。又，與比較例1相比，未反應物之生成量較少，於漿料穩定性或研磨特性之方面亦優異。[Method for Producing Silica Particle Dispersion] The method for producing the silica particle dispersion of the present invention includes the steps of: preparing a liquid I substantially containing an organic solvent; Liquid A, and liquid B containing alkaline catalyst and water, to hydrolyze and polycondense silane alkoxides to produce a dispersion liquid containing two or more primary particles linked to special-shaped silica particles. At this time, the time from the start of addition (start of reaction) until reaching the concentration of 70% of the concentration of silicon dioxide in the reaction system (dispersion liquid) at the end of addition (end of reaction) was defined as the total addition time (total reaction time ) of 20% or less. In this way, in the early stage of the reaction, the concentration of active silica particles (primary particles) in the system is rapidly increased, and the active co-cohesion of primary particles is promoted, so that special-shaped silica particles obtained by co-cohesion of primary particles can be efficiently produced . The time from the start of addition (start of reaction) until reaching the concentration of 70% of the silicon dioxide concentration in the system at the end of addition (end of reaction) is preferably less than 15% of the total addition time (total reaction time). Here, the so-called special-shaped silica particles formed by connecting two or more primary particles means that there are two or more particles (primary particles) grasped as a spherical or true spherical particle, preferably two or more particles. ~10 linked chain particles (refer to Figure 1). In addition, the silicon dioxide concentration in the system is measured by taking a sample every 10 minutes, drying 5 g of the sample at 1000°C for 1 hour, and obtaining it from the mass before and after drying (the following formula). Concentration of silica in the system (mass%) = (mass after drying/mass before drying) × 100 as the concentration of silica in the system from the beginning of addition (start of reaction) to the end of addition (end of reaction) The method of setting the time for the concentration of 70% of the total addition time to 20% or less of the total addition time (total reaction time) can include reducing the amount of liquid I, or increasing the addition concentration and addition speed of silane alkoxide at the initial stage of the reaction. <Liquid I (liquid prepared in advance in a container)> Liquid I substantially contains an organic solvent. Alcohols, ketones, ethers, glycols, esters, etc. are mentioned as an organic solvent. Among these, alcohols are preferred in terms of easily diffusing silane alkoxides and promoting hydrolysis uniformly and rapidly. More specifically, alcohols such as methanol, ethanol, propanol, and butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; methyl cellosolve, ethyl cellosolve, propylene glycol monopropylene Glycol ethers such as ethers; glycols such as ethylene glycol, propylene glycol, and hexanediol; esters such as methyl acetate, ethyl acetate, methyl lactate, and ethyl lactate. Among these, methanol or ethanol is more preferable, and methanol is especially preferable. These organic solvents may be used alone or in combination of two or more. Here, the term "substantially containing an organic solvent" means that impurities and the like inevitably included in the production process of the organic solvent may be contained, but nothing other than them is contained. For example, the organic solvent is at least 99% by mass, preferably at least 99.5% by mass. The amount of Liquid I is preferably 30% by mass or less, more preferably 15% by mass or less, and still more preferably 0.1 to 10% by mass, based on the total amount of Liquid A and Liquid B added. By setting the amount of liquid I to a small amount in this way, the concentration of active silica particles (primary particles) in the system can be rapidly increased at the initial stage of the reaction, and the co-attachment of primary particles can be promoted. Furthermore, in the previous reaction system, since the alkaline catalyst or water was put into the liquid I in advance, the composition in the system changed successively from the beginning of the addition (at the beginning of the reaction), so the silane alkoxide The hydrolysis conditions are not fixed, and unreacted products are likely to be produced. Also, the pH value at the beginning of the addition (at the beginning of the reaction) is high, but thereafter there is a tendency for the pH value to decrease, and when the added alkaline catalyst is insufficient, the pH value at the end of the addition (at the end of the reaction) is low There are many cases in 11, so it is easy to produce unreacted substances. On the other hand, in the present invention, since the liquid I substantially containing an organic solvent is used, the alkaline catalyst and water can be mixed with respect to the silane alkoxide during the reaction period from the start of addition (reaction start) to the end. The amount is set to be fixed. Thereby, the silane alkoxides added successively are always hydrolyzed under the same conditions, so the generation of unreacted products such as oligomers that have not grown to produce the target silica particles is suppressed. Also, it is possible to produce particles with uniform primary particle size. <Liquid A> Liquid A contains silane alkoxide, and preferably further contains an organic solvent. Usually, it substantially contains silane alkoxide, or substantially contains two components of silane alkoxide and an organic solvent. Furthermore, the words "substantially containing silane alkoxide" and "substantially containing two components" mean the same as above, which may contain impurities that are inevitably included in the production process of silane alkoxide or organic solvents, etc. However, other than these are not included, for example, it is 99 mass % or more, Preferably it is 99.5 mass % or more. What is represented by following formula [1] is mentioned as a silane alkoxide. X n Si(OR) 4-n・・・[1] In the formula, X represents a hydrogen atom, a fluorine atom, an alkyl group with 1 to 8 carbons, an aryl group or a vinyl group, and R represents a hydrogen atom with a carbon number of 1 to 8 8 is an alkyl group, aryl group or vinyl group, and n represents an integer of 0-3. As the silane alkoxide represented by the above formula [1], in addition to tetramethoxysilane and tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraoctoxysilane, Methyltrimethoxysilane, Methyltriethoxysilane, Methyltriisopropoxysilane, Ethyltrimethoxysilane, Ethyltriethoxysilane, Ethyltriisopropoxysilane, Octyl Trimethoxysilane, Octyltriethoxysilane, Vinyltrimethoxysilane, Vinyltriethoxysilane, Phenyltrimethoxysilane, Phenyltriethoxysilane, Trimethoxysilane, Triethyl Oxysilane, Triisopropoxysilane, Fluorotrimethoxysilane, Fluorotriethoxysilane, Dimethyldimethoxysilane, Dimethyldiethoxysilane, Diethyldimethoxysilane , Diethyldiethoxysilane, Dimethoxysilane, Diethoxysilane, Difluorodimethoxysilane, Difluorodiethoxysilane, Trimethylmethoxysilane, Trimethylethylsilane Oxysilane, Trimethylisopropoxysilane, Trimethylbutoxysilane, Trifluoromethyltrimethoxysilane, Trifluoromethyltriethoxysilane, etc. Among these silane alkoxides, it is especially preferable to use tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS) where n in the above formula [1] is 0 and the alkyl chain of R is relatively short. . When these are used, the hydrolysis rate becomes faster, the initial concentration of silica particles can be rapidly increased, and unreacted substances tend not to remain easily. Among them, tetramethoxysilane (TMOS) with a shorter alkyl chain is preferred. As the organic solvent of Liquid A, those exemplified for Liquid I above can be used, and it is preferable to use an organic solvent having the same composition as Liquid I. That is, when methanol is used for liquid I, it is preferable to also use methanol for liquid A. Here, when the liquid A contains an organic solvent, the concentration of the silane alkoxide relative to the organic solvent is, for example, 1.5 to 6.4 mol/L, preferably 2.0 to 6.0 mol/L. <Liquid B> Liquid B is what contains an alkaline catalyst and water, and usually consists of two components substantially. In addition, the term "substantially comprising two components" has the same meaning as that described in the above-mentioned liquid A. As the basic catalyst, compounds showing basicity such as ammonia, amine, alkali metal hydride, alkaline earth metal hydride, alkali metal hydroxide, alkaline earth metal hydroxide, quaternary ammonium compound, amine coupling agent, etc. can be used, Preferably ammonia is used. Here, the concentration of the alkaline catalyst relative to water is, for example, 1 to 24 mol/L, preferably 3 to 15 mol/L. <Reaction conditions, etc.> The method for producing the silica particle dispersion liquid preferably satisfies the following two conditions. (1) The molar ratio of the basic catalyst to the silane alkoxide in the reaction system during the period from the start of the addition of Liquid A and Liquid B to the end (the period from the beginning of the addition (start of reaction) to the end) is relative to The change rate of the initial value (catalyst ratio change rate) is 0.90 to 1.10, (2) In the reaction system during the period from the start of the addition of liquid A and liquid B to the end (the period from the start of the addition (start of the reaction) to the end) The change rate (change rate of water ratio) of the molar ratio of water to silane alkoxide relative to the initial value is 0.90 to 1.10. That is, it is desired to keep the rate of change of the catalyst ratio and the rate of change of the water ratio as small as possible during the period from the start of the addition (start of the reaction) to the end. As a specific aspect thereof, as mentioned above, the method of reducing the amount of the alkaline catalyst and water contained in the liquid I as much as possible in advance, thereby suppressing the rate of change of the catalyst ratio and the rate of change of the water ratio. Also, from the start of the addition (start of the reaction) to the end, the addition conditions such as the addition speed of the liquid A and the liquid B are set as constant as possible to suppress the catalyst ratio change rate and the water ratio change rate method. For example, by using a high-precision pump, it is possible to suppress variations in the addition rates of liquid A and liquid B. Thereby, the silane alkoxide added successively is always hydrolyzed under the same conditions, and the generation of unreacted products such as oligomers that do not grow to produce the target silica particles is suppressed. Therefore, the step of removing unreacted substances can be omitted, and the silica particle dispersion liquid can be efficiently produced. In addition, the produced silica particle dispersion hardly contained unreacted substances such as oligomers. Therefore, a silica particle dispersion liquid and an abrasive material having excellent stability as an abrasive material and good abrasive properties can be obtained. Furthermore, particles with uniform primary particle diameter can be produced. Here, the molar ratio of alkaline catalyst to silane alkoxide (alkaline catalyst/silane alkoxide) and the molar ratio of water to silane alkoxide (water/silane alkoxide) are respectively Calculated based on the measured value of added weight. At this time, it is assumed that the hydrolysis and polycondensation reactions of silane alkoxide occur instantaneously, and the alkaline catalyst is not released outside the system. The rate of change of the catalyst ratio and the rate of change of the water ratio are calculated by calculating the molar ratio in the reaction system based on the measured value of the added weight every specific time (for example, every 10 minutes), and dividing it by the value of the initial molar ratio. In addition, the so-called initial value means the molar ratio (theoretical value) immediately after adding liquid A and liquid B. As mentioned above, the catalyst ratio change rate is preferably from 0.90 to 1.10, more preferably from 0.95 to 1.05, and still more preferably from 0.98 to 1.02. As described above, the rate of change of the water ratio is preferably from 0.90 to 1.10, more preferably from 0.95 to 1.05, and still more preferably from 0.98 to 1.02. Also, the addition rate of the silane alkoxide is preferably at least 0.005 mol/min, more preferably at least 0.01 mol/min, and still more preferably at least 0.02 mol/min from the start of the addition (start of the reaction) to the end. By adding silane alkoxide at such a rate, it is possible to suppress generation of unreacted products such as oligomers of silane alkoxide that do not grow to the target silica particles. Also, in the initial stage of the reaction, a large number of primary particles whose surfaces are active can be formed, and the primary particles can be contacted and cohesive, and the cohesive particles can be further grown as seed particles. Furthermore, in the reaction system from the start of the addition (start of reaction) to the end, the molar ratio of the basic catalyst to the silane alkoxide is always 0.20 or more, and the molar ratio of water to the silane alkoxide Always above 2.0. That is, it is preferable to keep the alkaline catalyst and water at a specific amount or more relative to the silane alkoxide between the addition (during the reaction). By allowing the alkaline catalyst and water to react while maintaining a certain amount or more in this way, hydrolysis can be sufficiently advanced, and the residue of unreacted silane alkoxide or the generation of unreacted products can be suppressed. In addition, the molar ratio of the alkaline catalyst to the silane alkoxide and the molar ratio of water to the silane alkoxide are the same as the above, and they are calculated based on the actual value of the added weight. Here, in the reaction system from the start of addition (start of reaction) to the end of the period, the molar ratio of the basic catalyst to the silane alkoxide is as described above, preferably 0.20 or more, more preferably 0.30 or more, More preferably, it is 0.50-1.00. Also, in the reaction system from the start of addition (start of reaction) to the end of the period, the molar ratio of water to silane alkoxide is as described above, preferably 2.0 or more, more preferably 3.0 or more, and still more preferably 3.5～15.0. In addition, in the reaction system at the end of the addition (at the end of the reaction), the pH is preferably at least 11, more preferably at least 11.2. In the previous reaction system in which the alkaline catalyst was placed in the liquid I in advance, the pH value was lower than 11 at the end of the reaction in many cases, which became the main cause of unreacted substances. In the present invention, as described above, the pH value at the end of the reaction can be made 11 or more by adding the amount of the alkaline catalyst or the amount of water fixed relative to the silane alkoxide. The reaction is usually carried out under normal pressure. The reaction temperature may be any temperature lower than the boiling point of the solvent used, but it is preferably from 0 to 65°C, more preferably from 10 to 50°C, in order to accelerate the precipitation of particles. The silica particle dispersion liquid produced by the production method of the present invention produces less unreacted substances such as oligomers of silane alkoxide. Therefore, it is not necessarily necessary to carry out refining treatments such as heat aging treatment, heat removal treatment, and ultrafiltration performed previously. Also, the silica concentration in the silica particle dispersion (reaction system) at the end of the addition (at the end of the reaction) is higher than that produced by the previous method, for example, it is 5% by mass or more, preferably 10% by mass or more , more preferably 10 to 25% by mass. [Silicon dioxide particle dispersion] The silica particle dispersion of the present invention contains more than 10% of special-shaped silica particles formed by connecting two or more primary particles with an average particle diameter (d) of 5 to 300 nm. The content of reactants is below 200 ppm. The silica particle dispersion liquid can be produced by the above-mentioned production method. Silica particle dispersion is useful for grinding materials, and can be used directly in the state of dispersion or dried. <Unreacted substance> The so-called unreacted substance refers to a silicon-containing compound whose reaction has not progressed to target silica particles. For example, unreacted raw material silane alkoxide or its low-molecular hydrolyzate (oligomer), particles much smaller than the target particle, etc. Specifically, it refers to the time when the aqueous dispersion of silica particles is centrifuged at a set temperature of 10°C and 1,370,000 rpm (1,000,000 G) for 30 minutes using a small ultracentrifuge CS150GXL manufactured by Hitachi Koki Co., Ltd. Silicon-containing compounds present in the supernatant. "Measurement method for the content of unreacted substances" is based on the silicon-containing compound (unreacted substances) present in the above-mentioned supernatant liquid, using the ICP (Inductively Coupled Plasma, Inductively Coupled Plasma) luminescence analysis manufactured by Shimadzu Corporation The Si measured by the device ICPS-8100 is used to calculate the SiO 2 concentration. Since the silica particle dispersion hardly contains unreacted substances such as oligomers, when used in abrasive materials, the particle stability in the abrasive material is excellent, and the adhesion to the substrate is reduced. In addition, it can suppress the adsorption of various chemicals added to the abrasive or the reaction with various chemicals, and effectively exert the effects of various chemicals. The silica particles contained in the silica particle dispersion have a three-dimensional polycondensation structure. The reason for this is that hydrolysis and polycondensation of silane alkoxide proceed on the basic side, thereby proceeding not only planarly (two-dimensionally) but three-dimensionally (three-dimensionally). Abrasive materials using particles with such a structure have higher particle dispersibility and can obtain sufficient grinding speed, so it is preferable. On the other hand, when hydrolysis and polycondensation are performed on the acid side, they proceed two-dimensionally, and spherical particles cannot be obtained. This structure can be confirmed by a transmission electron microscope or a scanning electron microscope, and can be judged based on the presence of particles. The average particle diameter (d) of the primary particles contained in the silica particle dispersion is 5 to 300 nm, which can be appropriately set according to the required polishing speed or polishing precision. The calculation method of the average particle diameter (d) is demonstrated using FIG. 1. FIG. FIG. 1 exemplifies a particle in which a single primary particle exists or a particle in which a plurality of primary particles are connected. The blackened portion is an image of the junction between particles, and the junction may also include spaces. The particle diameter d is obtained by measuring the longest diameter of the primary particle of each particle. The average particle diameter (d) is obtained by taking an electron micrograph, measuring the longest diameter d of the primary particle of each particle for arbitrary 100 particles, and obtaining it as an average value. Here, when the average particle diameter is less than 5 nm, the stability of the silica particle dispersion tends to be insufficient, and the particle diameter is too small to obtain a sufficient polishing rate. When the average particle size exceeds 300 nm, when used as an abrasive, it also depends on the type of substrate or insulating film, but scratches are likely to occur, and sufficient smoothness may not be obtained. The average particle diameter is preferably from 10 to 200 nm, more preferably from 15 to 100 nm. The silica particle dispersion liquid contains more than 10% of the special-shaped silica particles formed by the connection of two or more primary particles with an average particle diameter (d) of 5 to 300 nm, preferably more than 30%, and more Preferably it contains more than 50%. The special-shaped silica particles are not particularly limited as long as two or more primary particles are connected, but preferably about 2 to 10 primary particles are connected. Here, the number of connected primary particles of heteromorphic silica particles or the ratio of heteromorphic silica particles in the system (heteromorphic particle ratio) was obtained by observing 100 arbitrary particles by taking electron microscope photographs. The silica particles contained in the silica particle dispersion are preferably such that the respective contents of U and Th are less than 0.3 ppb, alkali metals, alkaline earth metals, Fe, Ti, Zn, Pd, Ag, Mn, Co, Mo, The respective contents of Sn, Al, and Zr are less than 0.1 ppm, and the respective contents of Cu, Ni, and Cr are less than 1 ppb. If it is within this range, it can be used as abrasive grains for high-integrated logic circuits with a wiring node of 40 nm or less, memory, and three-dimensional mounting. If the content of metal elements in these impurities exceeds the above-mentioned range and exists in a large amount, there is a possibility that metal elements will remain on the substrate polished using silica particles. The metal element causes poor insulation of the circuit formed on the semiconductor substrate and short-circuits the circuit. As a result, the dielectric constant of the film (insulating film) provided for insulation decreases, and the impedance in the metal wiring increases, resulting in slow response speed and increased power consumption. In addition, this kind of failure may also occur when metal element ions move (diffusion), use conditions or use for a long time. In particular, in the case of U and Th, since radiation is generated, even if a trace amount remains, it is not preferable in terms of causing malfunction of the semiconductor due to radiation. Here, the term "alkali metal" means Li, Na, K, Rb, Cs, and Fr, and the term "alkaline earth metal" means Be, Mg, Ca, Sr, Ba, and Ra. In order to obtain high-purity silicon dioxide particles with less content of such impurities, it is preferable to set the material of the device when preparing the particles to one that does not contain these elements and has high chemical resistance. Plastics such as Teflon (registered trademark), FRP (Fiber Reinforced Plastics, fiber reinforced plastics), carbon fiber, and alkali-free glass are preferred. Moreover, it is preferable to refine|purify by distillation, ion exchange, and filter removal about the raw material used. In particular, ethanol used for hydrolysis of alkoxides may contain metal impurities from tanks or the like, or catalyst residues during synthesis, and may require particularly high-precision purification. As a method of obtaining high-purity silica particles, as described above, there is a method of preparing raw materials with few impurities in advance and suppressing contamination from particle preparation equipment. In addition, impurities can also be reduced from particles prepared without adequately taking such countermeasures. However, when impurities are introduced into the silica particles, purification by ion exchange or filter removal may be inefficient and costly. Therefore, using this method, it is not practical to obtain silica particles with less impurity content. "Determination of Metal Element Content" Regarding the content of U and Th in silica particles, the content of alkali metals, alkaline earth metals, Fe, Ti, Zn, Pd, Ag, Mn, Co, Mo, Sn, Al, Zr, And the content of Cu, Ni, Cr, is to use hydrofluoric acid to dissolve silicon dioxide particles, heat to remove hydrofluoric acid, add pure water if necessary, use ICP inductively coupled plasma emission spectrum quality to the obtained solution An analysis device (for example, ICPM-8500 manufactured by Shimadzu Corporation) is used for measurement. EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. [Example 1] <Manufacture of silica particle dispersion (SA)> 300.0 g of methanol (liquid I) was kept at 50°C, and tetramethoxysilane (Tama Chemical Industry Co., Ltd. Co., Ltd., hereinafter the same) methanol solution (liquid A) 2994.4 g, and ammonia water (liquid B) 800.0 g. The silica concentration of the silica particle dispersion liquid at the end of the reaction was 14.2% by mass. After completion of the addition, aging was carried out at the temperature for 1 hour. The solvent was replaced with pure water to obtain a silica particle dispersion (SA) having a silica concentration of 20% by mass. Table 1 shows detailed treatment conditions and various measurement results. In addition, the temporal changes of the catalyst ratio change rate and the water ratio change rate are shown in FIG. 2 . Furthermore, the change of the silicon dioxide concentration in the system is shown in FIG. 3 . "Molar ratio of alkaline catalyst and water relative to silane alkoxide and its rate of change" The molar ratios of alkaline catalyst/silane alkoxide and water/silane alkoxide are measured based on the added weight The value is calculated assuming that the hydrolysis and polycondensation reactions of silane alkoxides occur instantaneously, and the alkaline catalyst is not released out of the system. After 10 minutes from the start of addition of liquid A and liquid B, the molar ratio in the reaction system per 10 minutes was calculated. The molar ratio (theoretical value) immediately after the addition of liquid A and liquid B was set as the initial value, and the change of the molar ratio of each substance in the system was compared by dividing the value obtained by the initial value. Si(OR) 4 ＋4H 2 O→Si(OH) 4 ＋4ROH (4 moles are consumed during hydrolysis) Si(OH) 4 →SiO 2 ＋2H 2 O (2 moles are released during polycondensation) "Oxygen dioxide in the system Silicon concentration> Samples are taken every 10 minutes, and 5 g of the sample is dried at 1000°C for 1 hour. According to the mass before and after drying, the concentration of silicon dioxide in the system is calculated (the following formula). Concentration of silica in the system (mass%) = (mass after drying/mass before drying) × 100 "Amount of unreacted matter" The amount of unreacted matter is based on the use of a small ultracentrifuge CS150GXL manufactured by Hitachi Koki Co., Ltd. , for the obtained silicon dioxide particle dispersion with a silicon dioxide concentration of 20% by mass, the silicon-containing compound present in the supernatant liquid when centrifuged at a set temperature of 10°C and 1,370,000 rpm (1,000,000 G) for 30 minutes ( Unreacted matter), compared with the SiO2 concentration obtained from the Si measured by the ICP emission analyzer ICPS-8100 manufactured by Shimadzu Corporation. "Average Particle Size of Primary Particles" The average particle size of primary particles is an electron microscope photograph taken of silicon dioxide particles. For any 100 particles, as shown in Figure 1, the part with the longest diameter of the primary particle (also with a chain) is measured. In the case of the short diameter direction of the shape particle), it is obtained in the form of its average value. <<CV value of primary particle diameter>> The CV value of primary particle diameter was obtained by calculation using the above-mentioned results. "Ratio of Irregular Silica Particles in the System (Irregular Particle Ratio)" Take electron microscope photos, observe any 100 particles, and calculate the ratio of Irregular Silica Particles formed by connecting two or more primary particles . "Number of Connected Primary Particles of Heteromorphic Silica Particles" Take electron microscope photos, observe 100 random particles, and calculate the average number of connected particles of each particle. <Manufacture of abrasive material (SA)> An abrasive material (SA) containing 3.0% by mass of silica particles produced in Example 1, 175 ppm of hydroxyethylcellulose (HEC), and 225 ppm of ammonia was prepared. "Stability Test of Abrasive (Slurry)" The stability of abrasive (slurry) was evaluated according to whether the abrasive (SA) prepared in <Manufacturing of Abrasive (SA) was cloudy or not. The results are shown in Table 1. No cloudiness: ○ Cloudiness: × "Grinding test" Use a polishing substrate (single crystal silicon wafer with a crystal structure of 1.0.0), install it in a polishing device (NF300 manufactured by Nano Factor Co., Ltd.), and use a polishing pad SUBA600 , Substrate load 15 kPa, table rotation speed 50 rpm, spindle speed 60 rpm, for the above abrasive (SA), polish the substrate for polishing at a rate of 250 ml/min for 10 minutes. Thereafter, it was washed with pure water and air-dried. Thereafter, the polished surface of the obtained polished substrate was observed, and the smoothness of the surface was evaluated by the following criteria (degree of scratches). The results are shown in Table 1. Scratches are barely visible. : ○ Slight scratches are seen. : △ Large-scale scratches were seen. : × Regarding the residue of the silicon dioxide component on the polished substrate, the degree of the residue was confirmed using a laser microscope (VK-X250 manufactured by KEYENCE Co., Ltd.), and evaluated by the following evaluation criteria. The results are shown in Table 1. Almost no residue is visible. : ○ A little residue is seen. : △ Large-scale residues were seen. : × [Example 2] <Manufacture of silica particle dispersion (SB)> 206.0 g of methanol (liquid I) was kept at 25°C, and tetramethoxysilane methanol was added simultaneously to liquid I over 10 hours Solution (liquid A) 2003.3 g, and ammonia water (liquid B) 784.0 g. The silica concentration of the silica particle dispersion liquid at the end of the reaction was 12.9% by mass. After completion of the addition, aging was carried out at the temperature for 1 hour. The solvent was replaced with pure water to obtain a silica particle dispersion (SB) having a silica concentration of 20% by mass. Table 1 shows detailed treatment conditions and various measurement results. In addition, the temporal changes of the catalyst ratio change rate and the water ratio change rate are shown in FIG. 4 . Furthermore, the change of the silicon dioxide concentration in the system is shown in FIG. 5 . Except using the silica particle dispersion liquid (SB), the abrasive material (SB) was produced in the same manner as in Example 1, and the stability test and the grinding test were performed in the same manner as in Example 1. The results are shown in Table 1. [Example 3] <Manufacture of silica particle dispersion (SC)> 150.0 g of methanol (liquid I) was kept at 60°C, and a methanol solution of tetramethoxysilane ( Liquid A) 2994.4 g, and ammonia water (liquid B) 800.0 g. The silica concentration of the silica particle dispersion liquid at the end of the reaction was 14.7% by mass. After completion of the addition, aging was carried out at the temperature for 1 hour. The solvent was replaced with pure water to obtain a silica particle dispersion (SC) having a silica concentration of 20% by mass. Table 1 shows detailed treatment conditions and various measurement results. In addition, the temporal changes of the catalyst ratio change rate and the water ratio change rate are shown in FIG. 6 . Furthermore, the change of the silicon dioxide concentration in the system is shown in FIG. 7 . A grinding material (SC) was produced in the same manner as in Example 1 except that the silica particle dispersion (SC) was used, and a stability test and a grinding test were performed in the same manner as in Example 1. The results are shown in Table 1. [Example 4] <Manufacture of silica particle dispersion (SD)> 500.0 g of methanol (liquid I) was kept at 40°C, and tetramethoxy was added simultaneously to liquid I over 8 hours and 20 minutes (500 minutes). 2794.4 g methanol solution of silane (liquid A) and 800.0 g ammonia water (liquid B). The silica concentration of the silica particle dispersion liquid at the end of the reaction was 14.2% by mass. After completion of the addition, aging was carried out at the temperature for 1 hour. The solvent was replaced with pure water to obtain a silica particle dispersion (SD) having a silica concentration of 20% by mass. Table 1 shows detailed treatment conditions and various measurement results. In addition, the temporal changes of the catalyst ratio change rate and the water ratio change rate are shown in FIG. 8 . Furthermore, changes in the concentration of silicon dioxide in the system are shown in FIG. 9 . Except for using the silica particle dispersion (SD), an abrasive material (SD) was produced in the same manner as in Example 1, and a stability test and a polishing test were performed in the same manner as in Example 1. The results are shown in Table 1. [Comparative Example 1] <Manufacture of Silica Particle Dispersion (RA)> Liquid I containing 2268.0 g of methanol, 337.5 g of pure water, and 94.5 g of 29% ammonia water was kept at 40°C for 160 minutes. Add 2170.0 g of tetramethoxysilane methanol solution (liquid A). The silica concentration of the silica particle dispersion liquid at the end of the reaction was 14.0% by mass. After completion of the addition, aging was carried out at the temperature for 1 hour. The solvent was replaced with pure water to obtain a silica particle dispersion (RA) having a silica concentration of 20% by mass. Table 1 shows detailed treatment conditions and various measurement results. In addition, the temporal changes of the catalyst ratio change rate and the water ratio change rate are shown in FIG. 10 . Furthermore, changes in the concentration of silicon dioxide in the system are shown in FIG. 11 . Except for using the silica particle dispersion (RA), an abrasive material (RA) was produced in the same manner as in Example 1, and a stability test and a polishing test were performed in the same manner as in Example 1. The results are shown in Table 1. Furthermore, in any of the Examples and Comparative Examples, the respective contents of U and Th in the silica particles were less than 0.3 ppb, and alkali metals, alkaline earth metals, Fe, Ti, Zn, Pd, Ag, Mn, Co , Mo, Sn, Al, Zr each content is less than 0.1 ppm, Cu, Ni, Cr each content is less than 1 ppb. 《Metal element content》 Regarding the content of each metal element in the silicon dioxide particles, the silicon dioxide particles are dissolved with hydrofluoric acid, heated to remove the hydrofluoric acid, and pure water is added as needed to obtain the obtained The solution is measured using an ICP inductively coupled plasma emission spectrometer (for example, ICPM-8500 manufactured by Shimadzu Corporation). [Table 1] As shown in Table 1, it can be seen that the silica particle dispersions produced in Examples 1 to 4 efficiently produced irregular-shaped silica particles. Also, compared with Comparative Example 1, the amount of unreacted matter produced was small, and it was also excellent in terms of slurry stability and polishing properties.
